MUSCLE PHYSIOLOGY

Detailed explanation-1: -Sliding-filament model of muscle contraction. The actin filaments slide past the myosin filaments toward the middle of the sarcomere. The result is shortening of the sarcomere without any change in filament length.

Detailed explanation-2: -Sarcomere shortening is the result of cyclic cross-bridge formation between the myosin “head” formed by the myosin heavy chain (MHC) and active sites on actin. The process is regulated by the thin filament associated proteins, troponin (Tn) C, I, and T, and tropomyosin.

Detailed explanation-3: -Muscle contraction occurs when sarcomeres shorten, as thick and thin filaments slide past each other, which is called the sliding filament model of muscle contraction.

Detailed explanation-4: -The contraction of myosin’s S1 region is called the power stroke, which requires the hydrolysis of ATP, which breaks a high-energy phosphate bond to release energy, resulting in force generation and shortening of an individual sarcomere.

Detailed explanation-5: -Shortening of sarcomere occurs when Z lines attached to actin filaments are pushed outwards.